Photoacoustic Spectroscopy Applied to the Study of Bone Consolidation in Fractures

Abstract:

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By using photoacoustic (PA) spectroscopy it was performed a study about bone
consolidation in fractures. It was obtained the optical absorption spectra of callus of male rat fractured bones at different consolidation times. From these spectra it was possible to observe the presence of alkaline phosphatase through their absorption peaks which were compared with characteristic peaks reported in the literature for this phosphatase. In this study we showed that alkaline phosphatase could be considered as an indicator of the repair process of bone fractures.

Abstract: Photo-thermo-refractive (PTR) glass belongs to a class of photosensitive multicomponent
silicate glasses which demonstrate photo-thermo-induced precipitation of a crystalline
phase. Photo-induced crystallization of sodium fluoride results in refractive index variations in
exposed areas of PTR glass which was successfully applied for phase hologram recording.
However, even if this glass is widely used for advanced optical applications such as the stabilization
of laser diodes or spectral beam combining, the detailed mechanism of its photosensitivity is not
well known. We present in this paper an analysis of the evolution of the absorption spectra of UVexposed
PTR glass at the early stages of the thermal treatment (nucleation). Absorption spectra were
measured on samples nucleated at constant temperature for different periods. Analysis of the
structure of these spectra shows that the optimum of the nucleation process is associated with the
appearance of a new absorption band in visible range that disappears when the crystal growth
process starts. Analogous study was performed during the nucleation process. High temperature
spectroscopic measurements were performed during the thermal treatment. It was found that
absorption spectra evolve with a change of temperature, i.e. the band structure of these spectra is
different whether or not the temperature is decreased below a temperature of ~400°C. We associate
this process with the change of phase of the silver bromide nuclei (liquid/solid) that appears during
the cooling or heating processes.

Abstract: Iron phthalocyanine (FePc) thin films prepared by thermally evaporated from as received and purified powders were studied. The molecular interaction between FePc thin films and acetone vapor was studies by X-ray photoemission spectroscopy (XPS) and optical absorption spectrometer. The core level XPS spectra and optical absorption spectra showed slightly different between the spectra before and after acetone exposure. For FePc film evaporated with purified powder, only the Fe 2p3/2 spectra at about 712 eV appeared and the height of peak dramatically decreased. Iron K-edge X-ray absorption near edge structure (XANES) spectra was used to investigate iron atom in as received and purified powders and also study the interaction between FePc molecule and methanol vapor. The X-ray diffraction pattern of as received, annealed and purified FePc powder were investigated to study the crystal reformation and Raman spectroscopy was used to investigate iron atom vibration in as received FePc film.

Abstract: Optical absorption of orthorhombic and hexagonal manganites RMnO3 (R= Pr3+, Gd3+, Sm3+, Eu3+, Ho3+, Tm3+, Er3+, and Yb3+) were studied in polarized light in the near- and mid-infrared range for the temperature range 80 - 300 K. Several spectral features associated with 4f-4f transitions of R3+ ions were found in the transparency window of RMnO3. Anisotropy of the absorption spectra in the range of multiplet 4f-4f transitions and changes in populations of the multiplet levels with temperature were observed.

Abstract: The transmittance, absorbance, and reflectance of PMMA/TiO2 composites, in different weight percentage of TiO2, prepared by a solution cast technique are investigated. The Optical transmission and UV-VIS absorption spectra have been recorded in the wavelength range 200nm-800nm for different compositions of TiO2 doped PMMA polyfilms. The absorption coefficient, optical (Direct/Indirect) energy gap, Refractive index, Optical Dielectric constant, Constant B, ratio of carrier concentration to the effective mass have been evaluated. The effects of doping percentage of TiO2 on these parameters have been discussed and behaviors of all parameters are investigated.